With concern about infection, transmission of AIDS, hepatitis and similar incurable diseases of the blood, methods and devices to enclose the used disposable needle tip have become very important and in great demand. Many approaches to guard the needle, protect users and/or otherwise prevent injury have been proposed. All of them are cumbersome, expensive and interfere with the normal and accepted procedure for the insertion of an over the needle catheter. Typical of such introducers is U.S. Pat. No. 4,846,805 wherein the shield slides over the flash chamber body to engage the catheter and lock about the used needle tip.
Specifically, after the catheter has been inserted by an over the needle procedure and blood flashback has been observed, the catheter is advanced and/or the needle is withdrawn. After the catheter is inserted into the vessel as desired and the needle is withdrawn and discarded, protection of the used needle tip becomes important. Needle guards are of three types which either hide the withdrawn needle within the needle carrying hub, require replacement of a separate needle guard or include a sliding shield which can be positioned distally over the used needle. Some of these types of guards lock to secure the guard in the needle protecting position thereby preventing injury.
Those needle guards are cumbersome and interfere with the single hand over the needle catheter placement procedure as disclosed in Stanley, U.S. Pat. No. 3,714,945. The needle tip cover disclosed herein does not interfere with or require any additional steps, procedures or cumbersome mechanisms which interfere with the accepted over the needle technique.
U.S. Pat. No. 3,134,380 has a needle shield for a hypodermic needle and that needle shield is not provided to prevent infection but is included to preserve sterility and to hide the needle prior to use. The device therein includes a compressible resilient sleeve which is carried on the distal end of a syringe barrel to extend outwardly therefrom over the needle and its tip. The sleeve is axially collapsible during placement of the needle in the vessel and reextends due to the resilience of the sleeve as the needle is extracted from the vessel. The distal end of the sleeve is arranged to be carried about the needle and in its extended position rests beyond the tip. No means of locking the sleeve in the extended position is disclosed.
U.S. Pat. No. 4,846,804 has a needle tip protector with a collapsible sleeve disposed about the shank of the needle and a protective cap located at the distal end thereof. The cap surrounds and encloses the tip of the needle. A sealing member is located within the cap to enclose the tip until the needle is pushed through the sealing member. Similarly, U.S. Pat. No. 3,354,881 has a compressible device extending over the needle shank. Rubber septa are provided at the opposite ends of the compressible device so as to surround the needle.
U.S. Pat. No. 4,139,009 has a needle tip protector with a permanently attached cover surrounding the needle and a number of elastic arms which extend along the length of the needle. The arms are constructed so as to bow outwardly from the needle shank when the needle is pressed against and into the patient. U.S. Pat. No. 4,660,570 shows a needle tip protector with a membrane extending over the sharp point of the needle whereby penetration causes the needle to extend through the membrane and the skin of the patient.
U.S. Pat. No. 4,650,468 has a device with a sleeve concentrically placed about the needle shank. A safety shield at one end has a rubber membrane extending across an opening in the shield. The membrane is adapted to be pierced by the needle tip for use.